Spatial–Temporal Analysis of the Relationships between Agricultural Production and Use of Agrochemicals in Eastern China and Related Environmental and Political Implications (Based on Decoupling Approach and LMDI Decomposition Analysis)

Agrochemical inputs such as chemical fertilizers and pesticides have been recognized as sources of agricultural non-point source pollution and are controlled in order to prevent further deterioration of water pollution. In consideration of the available and effective measures to improve agricultural output value in a long-term, the key to the adoption of reduction control on agrochemical inputs is to ensure the decoupling relationship of agrochemical inputs to agricultural economic growth and to find out the endogenous growth of agrochemical inputs. This paper analyzed the relationship of agrochemical input consumption and agricultural output value in Eastern China by the Topia decoupling model. Interestingly, the transformation of expansive negative decoupling—expansive coupling—weak decoupling—strong decoupling was exposed, which can be used as a theoretical support to the source reduction control on agricultural non-point source pollution. The source reduction can be influenced of three factors: area factor, agricultural productivity factor and efficiency factor , which were decomposed by applying a log-mean Divisia index (LMDI) method, and the efficiency factor can promote the slowing down of the increase of agrochemical input consumption, while the agricultural productivity factor was the main factor to increase agrochemical input consumption; the area factor was not obvious. In addition to that, the formulation and implementation of source reduction control policies was affected by the differences of the spatial framework in Eastern China, where the source reduction control in different regions would be used to move ahead (or to delay).